Suspension of Belief

To the Editors:

In Henry Petroski's article entitled "Floating Bridges" (Engineering, July-August), he states that the Hood Canal Bridge must rise and fall with 16-foot tides while maintaining a smooth connection with land by way of a moveable truss. That is not correct. Actually, the Hood Canal Bridge does not rise and fall with the tide. Instead, the roadway is mounted on piers above anchored, submerged pontoons that stay completely under water even at the lowest tide. The tidal displacement of the piers is small enough that the pontoons can be held steady without large movement of the roadway.

Theodore Katsanis
Bellevue, Washington

To the Editors:

I read with great interest Professor Petroski's article on floating bridges, especially because I'm a native of Curacao in the Netherlands Antilles. Curacao's floating Queen Emma Bridge was built in 1888, more than a century before the 2002 opening of Osaka Harbor's Yumemai Bridge, which he describes as the world’s first swinging, floating bridge. Our "Floating Lady" still functions as a major connection between the east and west sides of Willemstad, the capital city, and it still swings open many times a day to admit ships to the harbor.

Marie L. Raman
Science and Mathematics Department
National Technical Institute for the Deaf
Rochester Institute of Technology
Rochester, New York